The common practice for snapping a chalkline string as is currently known in the construction industry involves the participation of two individuals. One person holds the free end of the chalkline string at a predetermined position, representing the terminus of a chalk line to be applied on for example the surface of a wall or floor. The other person proceeds to the desired location for the opposite terminus of the chalk line, paying-out the chalkline string from a conventional chalkline string box. The chalkline string is thereafter "snapped," causing a quantity of the chalk contained in the chalkline string to adhere to the surface against which it is snapped.
The aforementioned procedure has several disadvantages. In many instances, a second individual is not available to assist in snapping a chalkline string. For the case in which a second individual is available, that person must stop whatever he is doing and assist the chalkline box operator in applying the chalk line. This, of course, results in reduced productivity, especially where the second individual is working quite a distance from the desired chalk line location. In the case where the second individual is working at an elevated location, such as on a ladder or scaffold, there is an increased risk of injury associated with his descent and ascent in order to assist in snapping the chalkline string.
Construction industry personnel have attempted to minimize productivity and safety losses associated with this operation. One method has been for the individual to attach the free end of the chalkline string to the surface upon which the chalk line is to be placed, utilizing a nail or other anchoring device. This could result in the anchoring device falling off or shifting away from the predetermined mark when tension is applied to the chalkline, especially when angled lines are desired, thereby resulting in an inaccurate chalk line mark. Furthermore, the surface against which the chalkline string is to be snapped may not be amenable to a penetrating anchoring device. For example, a nail could not easily be driven into the surface of a concrete floor, or a nail pressed into foam insulation wallboard could not secure the free end of a chalkline string when the chalkline string is placed under tension.
U.S. Pat. No. 2,589,500 discloses a conventional chalkline box, including a ring at the free end of the chalkline which is intended to be placed over a nail or penetrating anchor placed into the surface against which the chalkline string is to be snapped.
U.S. Pat. No. 3,675,735 discloses mounting means for positioning and anchoring the free end of a chalkline string, utilizing a spring-loaded rod mounted on a ladder. Such a device is limited in its usefulness to the application of chalk lines only at locations accessible by a ladder.
Finally, U.S. Pat. No. 4,731,933 discloses a chalkline box in combination with a protractor. The device is useful for accurately snapping angled chalk lines, but still requires the participation of a second person to accurately locate and anchor the free end of the chalkline.
It would be desirable to construct a simple chalkline holding device, which would permit an individual to quickly and accurately apply a chalk line to a surface without assistance from another. Such a device should be inexpensive, easy to use, and adjustable for use on a wide variety of surfaces and for placing chalk lines at various angles.